<p>  Scientists do not 100% know how the universe began.</p><p> “The Big Bang theory” is the most widely accepted theory.</p><p> ______years ago all the matter in the universe was </p><p> contained in a small package.</p><p> It had infinite ______. (Something with ______</p><p>______is called a “singularity”)</p><p> Lots of ______and ______built up until the package </p><p> exploded.</p><p> All ______in the universe is a result of this explosion.</p><p>Timeline Since the Big Bang Evidence</p><p> The universe is ______(remember space is cold!)</p><p> The universe is ______.</p><p>Formation of Our Solar System</p><p> The Sun is about ______years old.</p><p> The planets are about ______years old.</p><p>Expanding Universe</p><p> Doppler Effect</p><p>As the ambulance approaches, the sound waves from its siren are ______towards the observer. As the ambulance recedes, the sound waves are ______relative to the observer.</p><p>By the change in pitch of the siren, you can determine if the ambulance is coming ______or speeding away.</p><p>Red Shift/Blue Shift</p><p>Light behaves the same way as sound waves. If a star is moving ______to us, the light it gives off gets squeezed together, which makes it appear ______than it actually is. </p><p>If it is moving away from us, the light gets stretched out, which makes it appear more ______than it really is.</p><p>Formation of Our Solar System</p><p> ______(the most widely accepted theory)</p><p>A large nebula condensed into a star, but in the process also formed an outer ring of material which became the planets.</p><p> ______</p><p>A star collided with the Sun and the debris formed the planets.</p>